Modulable Photocatalyzed Strategies for the Synthesis of α-<i>C</i>-Glycosyl Alanine Analogues via the Giese Reaction with Dehydroalanine Derivates
作者:Lorenzo Poletti、Alessandro Massi、Daniele Ragno、Federico Droghetti、Mirco Natali、Carmela De Risi、Olga Bortolini、Graziano Di Carmine
DOI:10.1021/acs.orglett.3c01660
日期:2023.7.7
Herein, we present the α-selective Giese reaction between pyranosyl/furanosyl bromides and dehydroalanine analogues, which provides access to a library of highly valuable α-C-glycosyl alanines. The key C-glycosyl radical is generated through photocatalysis by either the new generation copper(I) complex [(DPEPhos)(bcp)Cu]PF6 or [Ru(bpy)3](BF4)2. The reactions proceed smoothly, affording the desired α-C-glycosyl
在此,我们提出了吡喃糖基/呋喃糖基溴与脱氢丙氨酸类似物之间的α-选择性吉斯反应,该反应提供了获得高度有价值的α- C-糖基丙氨酸库的途径。关键的C-糖基自由基是通过新一代铜(I)络合物[(DPEPhos)(bcp)Cu]PF 6或[Ru(bpy) 3 ](BF 4 ) 2的光催化作用产生的。当使用 1,4-二氢-2,6-二甲基-3,5-吡啶二甲酸二乙酯 [Hantzsch 酯 (HE)] 作为反应剂时,反应顺利进行,以高达 99% 的产率提供所需的 α-C-糖基丙氨酸。添加剂。氮,氮-二异丙基乙胺 (DIPEA) 已被选为两个方案中的还原剂。通过瞬态吸收光谱进行的机理研究揭示了C-糖基自由基形成中的卤素原子转移 (XAT) 过程。